SAT-060 Assessing the Effect of Somatostatin Therapy on Glucose Control During Treatment For Neuroendocrine Tumors

Abstract Disclosure: S.D. Mohan: None. T. Htet: None. J. Lim: None. Introduction: Somatostatin analogues (SSAs) are used to treat carcinoid syndrome associated with neuroendocrine tumors (NETs) and provide an anti-proliferative effect. NETs can be slow growing and patients may be on SSA therapy for many years. Hence there is a need to better understand the long-term side effects of SSA therapy. Studies hypothesise that long term use of SSAs can affect glucose homeostasis due to the inhibition of pancreatic release of insulin. However, SSAs also alter the release of other hormones including glucagon, glucagon-like peptide 1 and hormones that effect gastric emptying. It is unclear whether patients with NETs have a predisposition to develop diabetes or hyperglycemia due to their underlying pre-treatment metabolic risk factors, hormonal hypersecretion from the neuroendocrine tumor itself, tumor mass effect when the pancreas is involved or if it is solely related to SSA therapy Methods: We performed a retrospective audit of 68 patients receiving SSA treatment for NET at a major neuroendocrine referral centre in Sydney, New South Wales, Australia to review pre and post SSA treatment glucose control. Sixty-two patients were diagnosed with gastroenteropancreatic tumors and 9 of these patients underwent a pancreatectomy. 22 patients received octreotide and 46 patients received lanreotide SSA treatment. 47 patients received concomitant lutate therapy. The median duration of somatostatin therapy was 2.6 years and lutate therapy was given every 8 weeks for 4 to 6 cycles. Results: Twenty patients (29.4%) had pre-existing diabetes prior to SSA commencement. Of these patients, 16 (80%) demonstrated worsening glucose control during SSA therapy. 3 patients remained stable and 1 patient did not have documented BGL monitoring. Nine patients (13%) had a new diagnosis of diabetes during follow up. However, routine monitoring of BGLs and HbA1c was not performed with only 21 patients (31%) having a test prior to treatment and 28 patients (41%) having a documented test for the duration of their SSA therapy. Patients undergoing lutate therapy had routine venous blood gas analysis which identified 18 patients with newly diagnosed hyperglycaemia (>11.1 mmol/L) but did not proceed to HbA1c testing. The low rate of screening suggests the rate of worsening glucose control or undiagnosed diabetes is likely higher than our data indicates. Discussion: Patients receiving SSA therapy in our NET referral centre do not have routine monitoring of their glycemic parameters. This is likely to lead to under-diagnosis of diabetes or worsening glycemic control. Clinicians and patients would benefit from a protocol to guide screening to ensure a timely diagnosis and appropriate treatment. Presentation: Saturday, July 12, 2025